The pathology of mouse models of human cancers and related diseases are studied and characterized using routine and new state-of-the-art pathology techniques including histopathology, immunohistochemistry, ultrastructure, in situ hybridization, image analysis, digital imaging and other methods to detect gene expression. Mouse models include targeted mutants with lymphomas and leukemias and mammary carcinomas and transgenics with mammary, prostate, and liver carcinomas.